Engine starter



1943. J. w. FITZ GERALD $307, 07

ENGINE STARTER Filed June 27, 1941 ill w a.

Patented Jan. 5, 1943 one stares ear a re" Briggs a Stratton Corporation,

tis., a corporation of Delaware Application June 27, 1941, Serial No. 399,973

2 Claims.

This invention relates to engine starters of the Milwaukee,

automatically meshed and demeshed type and means for holding the pinion in its retracted position.

In the operation of starters of this type it is essential to provide some means for holding the pinion against drifting or creeping forwardly into engagement with the ring gear while the engine is in operation. Heretofore, this means has has as its purpose the provision of improved taken various forms some of which have been successful and others not,

One of the faults of many of the past anticreep devices has been their opposition to traversal of the pinion toward driving position during operation of the starter; and it is therefore an object of this invention to provide an antifrendered inactive or disabled as a consequence to revolution of the power driven portion of the. starter in the' event it is not immediately released to thereby free the pinion for unhindered and unrestricted traversal toward driving position.

Another consequence of starters of this type especially when used on high-speed engines has preventing rebound.

It is thus a further object of thisinvention to provide a simple manner of combining these two devices into a single unit and for controlling both of them from the same centrifugally responsive means.

With the above and other objects in view which will appear'as the description proceeds, this invention resides in the novel construction, combi- .creep device for automatic starterswhich is Figure '2 is a cross sectional view taken through Figure 1 onthe plane of the line 2-2;

Figure 3 is. a perspective view of the starter;

Figure 4 is a fragmentary sectional View taken through Figure 2 on the plane of the line 4-4; a Figure 5 isa top view of a portion of the starter .to "show the application of this invention thereto; .and

Figure 6 is an enlarged sectional View similar to Figure 2 but illustrating a slightly modified embodiment of the invention. a

. Referring now particularly to the accompany- 'ing drawingiin which like numerals indicate like parts the numeral 5 designates a starter drive shaft which'a's is customary is the armature shaft of an electric motor 6.

The starter, designated generally by the nu- V meral' [is mounted on the shaft and includes a pinion 8 movable to and from a driving position meshed with. aring gear 9 on an engine (not shown) toibe started. V

The specific construction of the starter forms no part of this invention and hence need not be described in detail. Itissufiicient to state that the drive shaft 5 has a power or actuator unit indicated generally by the numeral i0 fixed thereto to revolve with the shaft and that the pinion or starter gear has a cylindrical extension or sleeve 1 l internally threaded to receive a screw threaded part l2 of the power or actuator unit.

A rubber collar or ring I3 incorporated in the power or actuator unit provides a resilient drivnation and arrangement of parts substantially as hereinafter described, and more particularly defined by the appended claims, it being understood that such changes in theprecise embodiment of the hereindisclosed invention may be made as come within the scope of the claims.

The accompanying drawing illustrates two complete examples of the physical embodiment ofthe invention constructed in accordance with the best modes so far devised for the practical application of the principles thereof, and in which? Y Figure 1 is a side View of an engine starter embodying this invention, parts thereof being broken away and shown in section;

ing connection between the shaft 5 and the screw member 1 2 in the manner well understood to those skilled in the art. The rubber ring or collar is confined between driving and driven flanges I3 and Hirespectively. The latter, which is fixed to the screw member 52 has a pivot post I5 projecting therefromand medially'pivoted on this post is a latch member I6. i The latch member i6 is preferably formed from sheet metal and is substantially in the form of a rectangular box having front and back side walls I! and i8 medially apertured to receive the pivot post, and end walls [9 and 29.

The end walls i9 and 29 have lugs 19' and 20' projecting therefrom toward the axis .of the starter to be engageable in an annular groove 2! in the cylindrical sleeve or extension ll of the pinion. The tongues 19 and 20' are so positioned with relation to each other and the diameter of the sleeve N that only one of them can be engaged in the groove 21 at any given time.

The rear and front edges of the tongue 19 are inclined or rounded so that the tongue can be cammed out of the groove 2| while the rear or inner edge of the tongue 20' is square, and its outer or front edge is inclined to provide a cam surface 22.

A torsion spring 23 coiled about the pivot post between the side walls of the latch member imposes a clockwise turning moment on the latch member when viewed as in Figure 2 tables the same to a position at which the tongue I9 engages in the groove 2|. In this position the other tongue 20' is of course lifted a substantial distance out of the groove.

Extending out from the end wall I9 of the latch member is a weightedarm 24 which pro-- vides centrifugally responsive means operable in opposition to the bias of thespring 23 when the starter is spinning to hold the tongue l9 out of the groove 2| and hold the tongue 20' in posi-' tion to cam itself into the groove upon retraction.

of the pinion.

By virtue of the square .inneredgeofjthe tongue 20' its engagement in the. groovev 2.l effectively prevents rebound of. the pinion, while engagement of the tongue IS) in the groove 2| serves as an anti-drift or anti-creep device to prevent the pinion from creeping forwardly into engagement with the ring gear when the starter is not in operation but the engine is running.

If, when the starter begins to operate, the tongue or detent l9 does. not immediately cam out of the groove, centrifugal force acting on the weight 24 will lift the same out ofthe groove H and free the pinion for traversal toward its driving position.

By virtue of the balance of forcesbetween the spring 23 and the centrifugal. force acting on'the weight 24 thetongue 20'xcannot engage in the groove before the pinion begins its traversal toward driving position, and" the instant such forward advance of the pinion starts, the square shoulder on the rear of the tongue 20 prevents engagement of the tongue in the groove.

However, as noted hereinbefore when the starter is spinning at the speed it reaches during the starting operation, the weight 24 throws the latch member to the position at which. its tongue 20' lies in the path of the end of the sleeve H so that upon retraction of the pinion when the engine starts, the cam surface 22 on the front edge of the tongue 20' cams the latch up over the end of the sleeve to enable'engagement of the tongue 20 in the groove.

Such engagement prevents the objectionable rebound and obtains until the speed of the starter rotation decreases sufliciently to allow the spring 23 to overcome the centrifugal force acting on the latch whereupon the tongue I 9 is engaged in the groove as noted hereinbefore;

In the embodiment of the invention shown' in Figure 6 the rebound prevention feature of the invention is omitted, but in all other respects the device operates in the manner described. To this end the latching member is pivoted at one end and has but one detent or'tongue 25 at its free end to be yieldingly urged into thegroove 2| by the torsion spring and to be lifted out of the groove by the weight 24 responding to centrifugal force .as the. starterbegins to spin.

From the foregoing description taken in connection with the accompanyingdrawing, it will be readily apparent that thisiinventi'on provides an improved manner of guarding against drifting or creeping of the pinion toward driving position and that it provides a simple manner of incorporating this function with that of an anti-rebound device.

What I claim as my invention is:

1. In an engine starter: a drive shaft; a driving member movable along the shaft to and from an operative driving position engaging a member of an engine to be started; an internally screw threaded sleeve having one end joined to the driving member and having an annular shoulder adjacent to but spaced inwardly of its opposite end; actuating means drivingly connected with the shaft to rotate therewith and having a screw threaded connection with said sleeve for efiecting traversal of the driving member toward operative driving position during initial operation of the starter and for retracting the drivingmembernto an inoperative retracted position upon starting of the engine; a latch member medially pivoted on said actuating means to rotate therewith, said latch member having latch parts at opposite sides of its pivot engageable behind said shoulder on the sleeve in the retracted position of the driving member to oppose traversal of the driving member toward operative position, said parts beingso disposed with relation to each other and the shoulder on the sleeve that only one of said parts can be engaged behind said shoulder at any given time; spring means biasing the latchmember to a position at which one of its latch parts engages behind the shoulder to prevent creepingvof the driving member toward its operative driving position; centrifugally responsive means on the actuating means connected with the latch member operable in response to centrifugal force during operation of the starter to overcomev said spring means. and swing thelatchmember. in a direction to disengage. said..first.-designated latch part thereof from the shoulder to thereby free the driving member for traversalv to its operative position, such traversal of the driving member to its operative position causing said opposite end of the sleeve to pass outwardly away from the latch member, said centrifugallyresponsive means maintaining the other of said latch parts in a potentially operative latching position in the path of said opposite end of the sleeve during cranking of theengine and retraction of the driving member to its inoperativeretracted position; and cooperatingcam.surfaces on the second-designated latch part. and said opposite end of the sleeve engageable. upon retraction of the driving member to. lift said seconddesignated latch part against the action of the centrifugally responsive means and allow passage of said opposite end of the sleeve thereunder for latching engagement of the second-designated latch part with said shoulder to preventrebounding of the. drive member- 2. In an engine starter; a drive.shaft;.a-driving member movable along. the shaft to andfrom an operative driving position engaging a .member of an engine to be started; an internally screw threaded sleeve having one. enddrivingly connected to the driving member and having an annular groove in its peripheryadjacent to but spaced inwardly of its oppositew end; actuating means drivingly connected with the shaft to rotate therewith and having a screw threaded connection with said. sleeve. for efEectingn-traversal of the driving member to an operative driving position upon initial operation of the. starter, and for retracting the driving memberto an inoperative retractedposition. upon starting of the engine; a centrifugally responsive latch member medially pivoted on said actuating means to rotate therewith and having latch parts at opposite sides of its pivot in line with the groove in said sleeve in the retracted position of the driving member, centrifugal force acting on the latch member during operation of the starter yieldably maintaining one of said latch parts disposed in the path of said opposite end of the sleeve; cooperating cam surfaces on said latch part and said opposite end of the sleeve engageable upon retraction of the driving member following starting of the engine to effect lifting of said latch part out of the path of the sleeve to thereby enable engagement of said latch part in the annular groove in the sleeve so as to prevent rebounding of the driving member after its retraction; and a spring biasing the latch member to a position disengaging said latch part thereof from the groove and engaging the other of said latch parts in said groove upon cessation of the effect of centrifugal force on the latch member to hold the driving member against creeping toward operative position while the starter is at rest.

JOHN W. FITZ GERALD. 

